The finite element method was used to simulate the currents of Jiaozhou Bay and the nearcoast areas, and then established the model of the transport and diffusion of suspended particulate matter there. The transport a...The finite element method was used to simulate the currents of Jiaozhou Bay and the nearcoast areas, and then established the model of the transport and diffusion of suspended particulate matter there. The transport and diffusion of dredged matter near the discharging field were estimated; and the results were used to analyze the effects of the suspended particulate matter on the marine environment.展开更多
There are many experimental approaches,field investigations and numerical calculations for movements of woods in a clear water and debris flow.However,kinematic conditions for accumulated logs and the interactions bet...There are many experimental approaches,field investigations and numerical calculations for movements of woods in a clear water and debris flow.However,kinematic conditions for accumulated logs and the interactions between a main flow and logs have not been fully evaluated.Mitigations for woods need taking into account the characteristics of tree species such as conifer and broad-leaf trees and of shapes such as root swells and crown.In the present study,we focus on the differences in specific weight of conifer and broad-leaf trees with some moisture in a sediment-water mixture flow with narrow flow width,and consider that conifer and broad-leaf tree are floating and submerged solid phase,respectively.Flume tests are conducted in steady flow of clear and debris flow over a rigid bed in order to evaluate conifer and broad-leaf tree movement in clear water and debris flow.Experimental data indicates that dimensionless transverse diffusion coefficient can be 0.1 to 0.4 and 0.3 to 0.9 in flow direction.Those diffusive characteristics seem to be independent of Reynolds number and Froude number,but dependent of bed slope,i.e.,gravity,though detailed considerations are needed to discuss about flow characteristics such as spatial eddy structures,momentum transfer induced by interactions of logs and so on.展开更多
This paper presents debris-flow numerical simulations using the Hyper KANAKO system,developed by the authors.The system uses the debris flow simulator KANAKO 2D equipped with a graphical user interface(GUI);hence,a us...This paper presents debris-flow numerical simulations using the Hyper KANAKO system,developed by the authors.The system uses the debris flow simulator KANAKO 2D equipped with a graphical user interface(GUI);hence,a user can easily produce appropriate landform data for simulations using standard laser profiler data,and visualize the results using a GIS.Hyper KANAKO was applied to the streams around Kiyomizu-dera in Kyoto,Japan.Kiyomizu-dera is a famous temple in Japan which is visited by numerous tourists throughout the year.We simulated a disaster scenario of debris flow caused by torrential rain.We set the hydrograph using rainfall intensity data,and set the landform data using information from the Geospatial Information Authority of Japan(GSI) and a digital elevation model(DEM).We evaluated different mesh sizes and also used a digital surface model(DSM) to consider the building heights.The simulation results showed that with small mesh size,the debris flowmoved through the roads,which seems realistic for a disaster situation.When buildings were considered,the flow direction changed,and a 1-m flow depth,which was deeper than in other cases,appeared in the flow path.This may pose a dangerous situation for evacuations.展开更多
To clarify temporal changes in the transboundary pollution, we analyzed SCPs （spheroidal carbonaceous particles） in bottom sediments of lakes in China, South Korea and Japan. SCPs provide an unambiguous record of an...To clarify temporal changes in the transboundary pollution, we analyzed SCPs （spheroidal carbonaceous particles） in bottom sediments of lakes in China, South Korea and Japan. SCPs provide an unambiguous record of anthropogenic atmospheric pollution in bottom sediments. Recently deposited SCPs in air and unmelted snow on Mt. Fuji were also characterized. The concentrarion and characteristics of SCPs reflected the environmental and industrial history of the area. Evidence of transboundary air pollution was observed after the 1980s in Yashagaike and Kotaniike ponds in Japan, which are located on the coast of the Sea of Japan. The concentration suggests that the pollutants originated from continental Asia, particularly after the 1980s. The chemical composition of the SCPs allowed the source of emissions to be identified. Chinese SCPs were found at Yashagaike and Kotaniike ponds in Japan, and at Songiiho and Urimji lakes in Korea. The size distributions showed that small SCPs are transported over long distances. On the summit of Mr. Fuji, SCPs transported by the prevailing westerlies from China were found in addition to SCPs emitted in Japan.展开更多
1.Control systems with distributed parameters can be considered as systems of infinite number of degrees of freedom. Therefore the optimal control problems in such systems can be treated naturally by using functional ...1.Control systems with distributed parameters can be considered as systems of infinite number of degrees of freedom. Therefore the optimal control problems in such systems can be treated naturally by using functional analysis. Let be a real Hilbert space, in展开更多
文摘The finite element method was used to simulate the currents of Jiaozhou Bay and the nearcoast areas, and then established the model of the transport and diffusion of suspended particulate matter there. The transport and diffusion of dredged matter near the discharging field were estimated; and the results were used to analyze the effects of the suspended particulate matter on the marine environment.
基金supported by Research Budget from Research and Development Center,NIPPON KOEI Co.,Ltd (Research theme:Modeling for debris flow with woods and their applicability)
文摘There are many experimental approaches,field investigations and numerical calculations for movements of woods in a clear water and debris flow.However,kinematic conditions for accumulated logs and the interactions between a main flow and logs have not been fully evaluated.Mitigations for woods need taking into account the characteristics of tree species such as conifer and broad-leaf trees and of shapes such as root swells and crown.In the present study,we focus on the differences in specific weight of conifer and broad-leaf trees with some moisture in a sediment-water mixture flow with narrow flow width,and consider that conifer and broad-leaf tree are floating and submerged solid phase,respectively.Flume tests are conducted in steady flow of clear and debris flow over a rigid bed in order to evaluate conifer and broad-leaf tree movement in clear water and debris flow.Experimental data indicates that dimensionless transverse diffusion coefficient can be 0.1 to 0.4 and 0.3 to 0.9 in flow direction.Those diffusive characteristics seem to be independent of Reynolds number and Froude number,but dependent of bed slope,i.e.,gravity,though detailed considerations are needed to discuss about flow characteristics such as spatial eddy structures,momentum transfer induced by interactions of logs and so on.
基金supported by JSPS KAKENHI Grant No.24710206,Grant-in-Aid for Young Scientists (B)
文摘This paper presents debris-flow numerical simulations using the Hyper KANAKO system,developed by the authors.The system uses the debris flow simulator KANAKO 2D equipped with a graphical user interface(GUI);hence,a user can easily produce appropriate landform data for simulations using standard laser profiler data,and visualize the results using a GIS.Hyper KANAKO was applied to the streams around Kiyomizu-dera in Kyoto,Japan.Kiyomizu-dera is a famous temple in Japan which is visited by numerous tourists throughout the year.We simulated a disaster scenario of debris flow caused by torrential rain.We set the hydrograph using rainfall intensity data,and set the landform data using information from the Geospatial Information Authority of Japan(GSI) and a digital elevation model(DEM).We evaluated different mesh sizes and also used a digital surface model(DSM) to consider the building heights.The simulation results showed that with small mesh size,the debris flowmoved through the roads,which seems realistic for a disaster situation.When buildings were considered,the flow direction changed,and a 1-m flow depth,which was deeper than in other cases,appeared in the flow path.This may pose a dangerous situation for evacuations.
文摘To clarify temporal changes in the transboundary pollution, we analyzed SCPs （spheroidal carbonaceous particles） in bottom sediments of lakes in China, South Korea and Japan. SCPs provide an unambiguous record of anthropogenic atmospheric pollution in bottom sediments. Recently deposited SCPs in air and unmelted snow on Mt. Fuji were also characterized. The concentrarion and characteristics of SCPs reflected the environmental and industrial history of the area. Evidence of transboundary air pollution was observed after the 1980s in Yashagaike and Kotaniike ponds in Japan, which are located on the coast of the Sea of Japan. The concentration suggests that the pollutants originated from continental Asia, particularly after the 1980s. The chemical composition of the SCPs allowed the source of emissions to be identified. Chinese SCPs were found at Yashagaike and Kotaniike ponds in Japan, and at Songiiho and Urimji lakes in Korea. The size distributions showed that small SCPs are transported over long distances. On the summit of Mr. Fuji, SCPs transported by the prevailing westerlies from China were found in addition to SCPs emitted in Japan.
文摘1.Control systems with distributed parameters can be considered as systems of infinite number of degrees of freedom. Therefore the optimal control problems in such systems can be treated naturally by using functional analysis. Let be a real Hilbert space, in
